Its goal has always been to create "the world's best service and warranty program" for any car on the market, he said, with the "overriding principle" being, "I want give people peace of mind" to ensure they have "the happiest possible transport experience."

The revisions to Tesla's service and warranty policies include three main points.

The $600-per-year service plan is now optional rather than mandatory.

This had been a source of considerable grumbling among Model S owners forced to pay $600 each year for a service plan on a car that, at least in theory, should need only wiper blades and tires replaced.

"We made a slight mistake," said Musk in a rare admission, "in making the service fee mandatory."

And, he revealed, unlike current automakers, his charge to the Tesla service department is "never to make a profit" from owners--just to break even.

That varies from today's conventional model, in which new cars are sold at relatively little profit by dealerships, which makes the bulk of their profits through service work and the sale of used cars.

Musk even quoted what he termed an adage in the car business: "Sales sells the first car, but service sells all the subsequent ones."

Any battery failure for any reason (within reason) is covered for the warranty term.

The goal here is not to require Model S buyers to read their owner manuals to understand how best to take care of their battery, Musk said.

"Any product that needs an owner's manual to work is broken," he said--a much-repeated Silicon Valley belief not always actually taken to heart by designers of consumer products.

And the company specifically included "user error" in its list of things that are now covered.

"This is to address electric-car concerns like, What if my battery dies?" said Musk.

"We want to say, don't worry about the battery, it's going to be fine."

Whether that includes leaving the car for long periods without plugging it in was not addressed on the company's call, but a notorious "bricking" incident with a Tesla Roadster received much coverage a couple of years ago.

Coverage excludes deliberate damage--owners attacking their battery packs with sledgehammers are likely not covered--but it seems a smart move on Tesla's part.

Loaner cars at Tesla Service Centers will be new top-of-the-line 85-kilowatt-hour Model S Performance versions.

And if owners decide they prefer the driving experience of the loaner to their own Model S, they can buy that car on the spot. Its price will be the new-car price minus 1 percent for each month it's been in service plus $1 for each mile it's covered.

Musk said that each service center will have two to 10 such cars, depending on its service volume. The fleet altogether would number about 100 cars.

These loaner cars will also be delivered to whatever destination the Model S owner specifies, by a valet service, and the company will pick up the car to be serviced wherever it's located.